Beatrix Potter was big business, very little of anything connected with her drawings and her books goes without some markings to indicate her name, copyrights and licensing. Like anything else though that's popular, others will copy a "Going Thing" as close as they can without actually labeling it as a legitimate original product.

The X marks here really don't tell us anything, but one of the cups looks like there is letters impressed on the bottom, what does it read. See if you can make it out and post back what you've found.